$ 16^{-\frac{1}{2}}$
Solution: $= \left(\dfrac{1}{16}\right)^{\frac{1}{2}}$ To simplify $\left(\dfrac{1}{16}\right)^{\frac{1}{2}}$ , figure out what goes in the blank: $\left(? \right)^{2}=\dfrac{1}{16}$ To simplify $\left(\dfrac{1}{16}\right)^{\frac{1}{2}}$ , figure out what goes in the blank: $\left({\dfrac{1}{4}}\right)^{2}=\dfrac{1}{16}$ so $ \left(\dfrac{1}{16}\right)^{\frac{1}{2}}=\dfrac{1}{4}$